Order LAMNIFORMES Berg, 1958
Family
JAEKELOTODONTIDAE Glückman, 1964
Jaekelotodus robustus (Leriche, 1921)

Hypotodus robustus in Nolf (1988).

All figured teeth were collected in late Palaeocene (middle or late Thanetian) localities.


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This species is described by Leriche (1905) as Odontaspis crassidens and was later by the same author referred to as Odontaspis robusta (1921). Nolf (1988) moved this species to the genus Hypotodus.

As Odontaspid teeth are slender with high and sharp cusplets, they can be easily differentiated from the massive robustus teeth with reduced cusplets. For this raison, Cappetta & Nolf (2005) attributed the species robustus to the genus Jaekelotodus, a genus Menner created in 1928 for trigonalis specimens from the late Eocene of Ukraine. Less convincing was the rejection (Cappetta & Nolf, 2005:246) of the by L.S. Glickman (1964) erected family Jaekelotodontidae as the family for these teeth; instead of the Odontaspididae.

In global teeth are large (up to 4cm) with massive roots and a distinct nutrient groove. The crown face is smooth on both sides. The anterior teeth are robust with mostly only one pair of sharp cusplets. Lower anteriors have a thick protuberance, while uppers are flatter. Lateral teeth often have two pair of cusplets. Upper laterals are very particular: a wide crown which is (strongly) distally inclined and rounded root tips. Lower laterals are more slender and straighter.

In our region, Jaekelotodus robustus was found in middle Thanetian, late Palaeocene (few specimens) to middle Eocene sediments.

Jaekelotodus robustus
(Leriche, 1921)
- Second lower anterior -
Late Thanetian, France
H=32mm
Jaekelotodus robustus (Leriche, 1921)
- upper lateral -
Late Thanetian (NP9), France
H=22mm
Jaekelotodus robustus
(Leriche, 1921)
- Third lower anterior -
Middle Thanetian, France
H=25mm

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CAPPETTA, H. & NOLF, D., 2005. Révision de quelques Odontaspididae (Neoselachii: Lamniformes) du Paléocène et de l'Eocène du Bassin de la mer du Nord. (Revision of some Odontaspididae (Neoselachii: Lamniformes) from the Palaeocene and Eocene of the North Sea Basin). Bulletin de l'institut Royal des Sciences Naturelles de Belgique, Sciences de la Terre/Aardwetenschappen, 75: 237-266.

GLICKMAN, L.S., 1964. About the Palaeogene sharks and their stratigraphic value. (In Russian), publication of the Academy of Science U.S.S.R., 229 pp.

LERICHE, M., 1905. Les poissons éocènes
de la Belgique. Mémoire du Musée royal d’Histoire naturelle de Belgique, 11(3): 49-228.

LERICHE, M., 1921. Sur les restes de poissons remaniés dans le Néogène de la Belgique. Leur signification au point de vue de l'histoire géologique de la Belgique pendant le tertiaire supérieur. Bulletin de la Société belge de Géologie, 30: 115-120.

MENNER, V.V., 1928. Les Sélaciens du Paléogène de Manghyschlak, d’Emba et du versant oriental d’Oural. Bulletin de la Société des Naturalistes de Moscou, Section Géologique, 6(3-4): 291-338.

NOLF, D., 1988. Fossielen van België. Haaien- en roggetanden uit het Tertiair van België. Koninklijk Belgisch Instituut voor Natuurwetenschappen, Brussel, 184 pp.

VAN DEN EECKHAUT, G. & DE SCHUTTER, P., 2009. The Elasmobranch Fauna of the Lede Sand Formation at Oosterzele (Lutetian, Middle Eocene of Belgium). Palaeofocus, 1: 1-57, 2 figures, 2 tables, 22 plates.